# Solar eclipse of January 15, 1991

An annular solar eclipse occurred at the Moon's ascending node of orbit between Tuesday, January 15 and Wednesday, January 16, 1991, with a magnitude of 0.929. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. An annular solar eclipse occurs when the Moon's apparent diameter is smaller than the Sun's, blocking most of the Sun's light and causing the Sun to look like an annulus (ring). An annular eclipse appears as a partial eclipse over a region of the Earth thousands of kilometres wide. Occurring 3.5 days after apogee (on January 12, 1991, at 11:00 UTC), the Moon's apparent diameter was smaller.
Annularity was visible in southwestern Western Australia, Tasmania, New Zealand and French Polynesia. A partial eclipse was visible for parts of Indonesia, Australia, Oceania, and Antarctica.

## Eclipse details

Shown below are two tables displaying details about this particular solar eclipse. The first table outlines times at which the moon's penumbra or umbra attains the specific parameter, and the second table describes various other parameters pertaining to this eclipse.
January 15, 1991 Solar Eclipse Times :
| Event | Time (UTC) |
| First Penumbral External Contact | 1991 January 15 at 20:51:57.9 UTC |
| First Umbral External Contact | 1991 January 15 at 21:57:45.6 UTC |
| First Central Line | 1991 January 15 at 22:00:52.7 UTC |
| First Umbral Internal Contact | 1991 January 15 at 22:04:00.1 UTC |
| First Penumbral Internal Contact | 1991 January 15 at 23:15:21.5 UTC |
| Greatest Duration | 1991 January 15 at 23:40:06.1 UTC |
| Equatorial Conjunction | 1991 January 15 at 23:44:29.4 UTC |
| Ecliptic Conjunction | 1991 January 15 at 23:50:36.9 UTC |
| Greatest Eclipse | 1991 January 15 at 23:53:51.3 UTC |
| Last Penumbral Internal Contact | 1991 January 16 at 00:32:36.2 UTC |
| Last Umbral Internal Contact | 1991 January 16 at 01:43:50.2 UTC |
| Last Central Line | 1991 January 16 at 01:46:55.5 UTC |
| Last Umbral External Contact | 1991 January 16 at 01:50:00.3 UTC |
| Last Penumbral External Contact | 1991 January 16 at 02:55:44.0 UTC |
January 15, 1991 Solar Eclipse Parameters :
| Parameter | Value |
| Eclipse Magnitude | 0.92901 |
| Eclipse Obscuration | 0.86306 |
| Gamma | −0.27275 |
| Sun Right Ascension | 19h49m11.2s |
| Sun Declination | -21°04'21.2" |
| Sun Semi-Diameter | 16'15.5" |
| Sun Equatorial Horizontal Parallax | 08.9" |
| Moon Right Ascension | 19h49m29.1s |
| Moon Declination | -21°18'36.9" |
| Moon Semi-Diameter | 14'53.1" |
| Moon Equatorial Horizontal Parallax | 0°54'37.7" |
| ΔT | 57.6 s |

## Eclipse season

This eclipse is part of an eclipse season, a period, roughly every six months, when eclipses occur. Only two (or occasionally three) eclipse seasons occur each year, and each season lasts about 35 days and repeats just short of six months (173 days) later; thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. In the sequence below, each eclipse is separated by a fortnight.
Eclipse season of January 1991 :
| January 15 Ascending node (new moon) | January 30 Descending node (full moon) |
| Annular solar eclipse Solar Saros 131 | Penumbral lunar eclipse Lunar Saros 143 |

## Related eclipses
### Eclipses in 1991

* An annular solar eclipse on January 15.
* A penumbral lunar eclipse on January 30.
* A penumbral lunar eclipse on June 27.
* A total solar eclipse on July 11.
* A penumbral lunar eclipse on July 26.
* A partial lunar eclipse on December 21.

### Metonic

* Preceded by: Solar eclipse of March 29, 1987
* Followed by: Solar eclipse of November 3, 1994

### Tzolkinex

* Preceded by: Solar eclipse of December 4, 1983
* Followed by: Solar eclipse of February 26, 1998

### Half-Saros

* Preceded by: Lunar eclipse of January 9, 1982
* Followed by: Lunar eclipse of January 21, 2000

### Tritos

* Preceded by: Solar eclipse of February 16, 1980
* Followed by: Solar eclipse of December 14, 2001

### Solar Saros 131

* Preceded by: Solar eclipse of January 4, 1973
* Followed by: Solar eclipse of January 26, 2009

### Inex

* Preceded by: Solar eclipse of February 5, 1962
* Followed by: Solar eclipse of December 26, 2019

### Triad

* Preceded by: Solar eclipse of March 17, 1904
* Followed by: Solar eclipse of November 15, 2077

### Solar eclipses of 1990–1992

This eclipse is a member of a semester series. An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating nodes of the Moon's orbit.
Solar eclipse series sets from 1990 to 1992 :
| Ascending node | Ascending node | Ascending node | Descending node | Descending node | Descending node |
| Saros | Map | Gamma | Saros | Map | Gamma |
| 121 | January 26, 1990 Annular | −0.9457 | 126 Partial in Finland | July 22, 1990 Total | 0.7597 |
| 131 | January 15, 1991 Annular | −0.2727 | 136 Totality in Playas del Coco, Costa Rica | July 11, 1991 Total | −0.0041 |
| 141 | January 4, 1992 Annular | 0.4091 | 146 | June 30, 1992 Total | −0.7512 |
| 151 | December 24, 1992 Partial | 1.0711 |

### Saros 131

This eclipse is a part of Saros series 131, repeating every 18 years, 11 days, and containing 70 events. The series started with a partial solar eclipse on August 1, 1125. It contains total eclipses from March 27, 1522 through May 30, 1612; hybrid eclipses from June 10, 1630 through July 24, 1702; and annular eclipses from August 4, 1720 through June 18, 2243. The series ends at member 70 as a partial eclipse on September 2, 2369. Its eclipses are tabulated in three columns; every third eclipse in the same column is one exeligmos apart, so they all cast shadows over approximately the same parts of the Earth.
The longest duration of totality was produced by member 28 at 58 seconds on May 30, 1612, and the longest duration of annularity was produced by member 50 at 7 minutes, 54 seconds on January 26, 2009. All eclipses in this series occur at the Moon’s ascending node of orbit.
Series members 39–60 occur between 1801 and 2200: :
| 39 | 40 | 41 |
| September 28, 1810 | October 9, 1828 | October 20, 1846 |
| 42 | 43 | 44 |
| October 30, 1864 | November 10, 1882 | November 22, 1900 |
| 45 | 46 | 47 |
| December 3, 1918 | December 13, 1936 | December 25, 1954 |
| 48 | 49 | 50 |
| January 4, 1973 | January 15, 1991 | January 26, 2009 |
| 51 | 52 | 53 |
| February 6, 2027 | February 16, 2045 | February 28, 2063 |
| 54 | 55 | 56 |
| March 10, 2081 | March 21, 2099 | April 2, 2117 |
| 57 | 58 | 59 |
| April 13, 2135 | April 23, 2153 | May 5, 2171 |
| 60 |
| May 15, 2189 |

### Metonic series

The metonic series repeats eclipses every 19 years (6939.69 days), lasting about 5 cycles. Eclipses occur in nearly the same calendar date. In addition, the octon subseries repeats 1/5 of that or every 3.8 years (1387.94 days). All eclipses in this table occur at the Moon's ascending node.
20 eclipse events between June 10, 1964 and August 21, 2036 :
| June 10–11 | March 28–29 | January 14–16 | November 3 | August 21–22 |
| 117 | 119 | 121 | 123 | 125 |
| June 10, 1964 | March 28, 1968 | January 16, 1972 | November 3, 1975 | August 22, 1979 |
| 127 | 129 | 131 | 133 | 135 |
| June 11, 1983 | March 29, 1987 | January 15, 1991 | November 3, 1994 | August 22, 1998 |
| 137 | 139 | 141 | 143 | 145 |
| June 10, 2002 | March 29, 2006 | January 15, 2010 | November 3, 2013 | August 21, 2017 |
| 147 | 149 | 151 | 153 | 155 |
| June 10, 2021 | March 29, 2025 | January 14, 2029 | November 3, 2032 | August 21, 2036 |

### Tritos series

This eclipse is a part of a tritos cycle, repeating at alternating nodes every 135 synodic months (≈ 3986.63 days, or 11 years minus 1 month). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee), but groupings of 3 tritos cycles (≈ 33 years minus 3 months) come close (≈ 434.044 anomalistic months), so eclipses are similar in these groupings.
Series members between 1801 and 2200 :
| June 26, 1805 (Saros 114) | May 27, 1816 (Saros 115) | April 26, 1827 (Saros 116) | March 25, 1838 (Saros 117) | February 23, 1849 (Saros 118) |
| January 23, 1860 (Saros 119) | December 22, 1870 (Saros 120) | November 21, 1881 (Saros 121) | October 20, 1892 (Saros 122) | September 21, 1903 (Saros 123) |
| August 21, 1914 (Saros 124) | July 20, 1925 (Saros 125) | June 19, 1936 (Saros 126) | May 20, 1947 (Saros 127) | April 19, 1958 (Saros 128) |
| March 18, 1969 (Saros 129) | February 16, 1980 (Saros 130) | January 15, 1991 (Saros 131) | December 14, 2001 (Saros 132) | November 13, 2012 (Saros 133) |
| October 14, 2023 (Saros 134) | September 12, 2034 (Saros 135) | August 12, 2045 (Saros 136) | July 12, 2056 (Saros 137) | June 11, 2067 (Saros 138) |
| May 11, 2078 (Saros 139) | April 10, 2089 (Saros 140) | March 10, 2100 (Saros 141) | February 8, 2111 (Saros 142) | January 8, 2122 (Saros 143) |
| December 7, 2132 (Saros 144) | November 7, 2143 (Saros 145) | October 7, 2154 (Saros 146) | September 5, 2165 (Saros 147) | August 4, 2176 (Saros 148) |
| July 6, 2187 (Saros 149) | June 4, 2198 (Saros 150) |

### Inex series

This eclipse is a part of the long period inex cycle, repeating at alternating nodes, every 358 synodic months (≈ 10,571.95 days, or 29 years minus 20 days). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee). However, groupings of 3 inex cycles (≈ 87 years minus 2 months) comes close (≈ 1,151.02 anomalistic months), so eclipses are similar in these groupings.
Series members between 1801 and 2200 :
| May 16, 1817 (Saros 125) | April 25, 1846 (Saros 126) | April 6, 1875 (Saros 127) |
| March 17, 1904 (Saros 128) | February 24, 1933 (Saros 129) | February 5, 1962 (Saros 130) |
| January 15, 1991 (Saros 131) | December 26, 2019 (Saros 132) | December 5, 2048 (Saros 133) |
| November 15, 2077 (Saros 134) | October 26, 2106 (Saros 135) | October 7, 2135 (Saros 136) |
| September 16, 2164 (Saros 137) | August 26, 2193 (Saros 138) | |